1. Field of the Invention
The present invention relates to an automatic personal search telephone system including an exchange which accommodates a plurality of subscriber telephone sets and an automatic personal search telephone apparatus which is connected to the exchange and which has a location telephone number registration means which, when receiving a personal identification number of a call terminating subscriber from a subscriber telephone set of a call originating subscriber, reads out from the registration area corresponding to that personal identification number the telephone number of the call terminating subscriber at the present location of the subscriber and outputs it to the exchange.
Along with the diversification of systems for electronic exchanges in recent years, there has been a spread in use of automatic personal search telephone systems which can call to a location where a call terminating subscriber has gone by giving personal identification numbers to specific individuals and having not the telephone number but the personal identification number entered. This enables much swifter and reliable connection of a call originating subscriber to a call terminating subscriber and improves the efficiency of work.
2. Description of the Related Art
As discussed in detail later, the automatic personal search telephone apparatus constituting the automatic personal search telephone systems of the past have included location telephone number registration means.
Such a location telephone number registration means is connected to an exchange which accommodates a plurality of subscriber telephone sets and, when receiving a personal identification number of a call terminating subscriber from the subscriber telephone set of the call originating subscriber, reads out from the registration area corresponding to the personal identification number the telephone number of the subscriber telephone at the current location of the call terminating subscriber and outputs it to the exchange 12. Therefore, when the call terminating subscriber goes somewhere, it is necessary to register in advance in the location telephone number registration means, through the exchange, the telephone number of the other subscriber telephone set at that location.
Once registered, if a call originating subscriber calls a call terminating subscriber using the personal identification number, even if the call terminating subscriber moves from the home position (place of subscriber telephone originally allocated to the subscriber telephones) to another location, the call originating subscriber can chase after the call terminating subscriber to the subscriber telephone set at the destination with the aid of the location telephone number registration means and therefore conversation between the two subscriber telephone sets becomes possible.
When the call terminating subscriber forgets to register again after once registering despite his going to another location or when he originally did not register his telephone number, the call terminating subscriber cannot be reached at his destination. Therefore, the personal search telephone function can only be used by the call originating subscriber when the call terminating subscriber has registered the telephone number of his destination at that destination and is at the registered destination. Therefore, even if the personal identification number is sent from the subscriber telephone set, when the call terminating subscriber has not recorded the telephone number of his destination at that destination or he is not at a destination where there is a subscriber telephone set with a telephone number of the destination, there is the problem that the call terminating subscriber cannot be reached.